A zero-knowledge proof is a cryptographic protocol that allows one party (the prover) to demonstrate to another party (the verifier) that a statement is true without revealing any information beyond the validity of the statement itself. This is achieved through mathematical constructions that enable verification without disclosure of the underlying data. Zero-knowledge proofs come in interactive and non-interactive variants, with applications ranging from authentication to blockchain privacy.
In the context of data protection and compliance, zero-knowledge proofs offer the potential to verify identity, credentials or compliance status without exposing sensitive personal data. This aligns strongly with data minimisation principles under the GDPR. As the technology matures, it is finding practical applications in privacy-preserving authentication, confidential transactions and secure multi-party computation, making it an increasingly relevant tool for organisations balancing security with privacy.